特异性免疫治疗对屋尘螨致敏哮喘小鼠NKT细胞的影响

目的:研究特异性免疫治疗(SIT)对哮喘小鼠自然杀伤T(NKT)细胞的影响。方法:24只BALB/C小鼠随机分为对照组(A组)、哮喘模型组(B组)、哮喘免疫治疗(SIT)组(C组),各8只。通过屋尘螨提取液(HDM)诱导建立哮喘小鼠模型并进行SIT治疗。检测各组小鼠的气道反应性、支气管肺泡灌洗液(BAlF)细胞计数及分类、ELISA检测IL-4、IFN-γ以及应用流式细胞仪检测NKT细胞数目,通过RT-PCR方法检测T-bet和GATA-3mRNA表达水平;HE染色观察小鼠肺组织的改变。结果:与B组相比,C组气道反应性明显下降(P0.01);BALF中细胞总数及嗜酸性粒细胞(EOS)数显著减少(P0.01);血清IL-4分泌显著降低(P0.01),IFN-γ显著升高(P0.01);NKT细胞数及其成熟型比例明显升高(P0.05);T-betmRNA表达水平明显升高(P0.01),且与NKT细胞数及其成熟型比例呈正相关性,GATA-3mRNA表达水平明显降低(P0.05),且与NKT细胞数及其成熟型比例呈负相关性。B组肺部管腔周围炎性细胞聚集,组织上皮损伤,组织水肿,而C组肺部变应性炎症明显减轻。C组其他各项指标接近A组。结论:哮喘的发生可能与NKT细胞失调相关,通过改变NKT细胞数目及其成熟型比例来调节GATA-3/T-bet的表达可能是SIT治疗哮喘的作用机制之一。

Effect of Specific Immunotherapy on the Expression of NKT Cells in House Dust Mite Extracts-Sensitized Murine Model

Objective: To investigate the effects of specific immunotherapy on the NKT cells in house dust mite(HDM) extracts-sensitized murine mode.Methods: Twenty-four BALB/C mice were randomly divided into three groups(with 8 in each group):control group(group A),asthma group(group B),SIT group(group C).The model of asthma were sensitized and challenged by HDM extracts while SIT group were subcutaneously immunized by HDM extracts.Twenty-four hours after the challenge,airway hyperresponsiveness of mice,total cellular score and cell classification in bronchoalveolar lavage fluid(BALF),the serum level of IL-4 were examined.IFN-γ was detected by ELISA,the number of NKT cells was determined by flow-cytometry,the expression of T-bet and GATA-3 mRNA was detected by RT-PCR,lung inflammation was detected by HE stain.Results: Compared with that in the group B,airway hyperresponsiveness in group C decreased(P<0.01).Specific immunotherapy significantly inhibit inflammation in mouse lung tissue pathological changes;Total cells and eosinophils(EOS) in BALF reduced significantly(P <0.01);Serum IL-4 was significantly lower(P <0.01);IFN-γ secretion was significantly higher(P <0.01);NKT cells number and the proportion of mature cells increased significantly(P <0.05);The level of T-bet mRNA expression increased significantly(P <0.01),and it was positively correlated with the number of NKT cells and its proportion of mature;The level of GATA-3mRNA expression were significantly lower(P <0.05),and it was negatively correlated with the number of NKT cells and its proportion of mature.The interstitial space surrounding the airway lumen was characterized by a densely mixed cellular infiltrate,epithelium tissue damage and tissue edema in group B,while lung inflammation of group C reduced considerably.Each test value of group C was substantially similar with that of group A.Conclusion: The occurrence of asthma may be associated with NKT cell dysfunction.By changing the number of NKT cells and its proportion of mature to regulate the GATA-3 / T-bet expression may be one of the mechanisms by which SIT was in the treatment of asthma.